ABSTRACT Nearly half of all patients starting dialysis are now over age 65. Median survival after initiating dialysis is short and patients experience frequent hospital stays, pain, fatigue, cognitive dysfunction and depression. Yet few receive palliative care in time to alleviate symptoms, document care goals and prepare for end of life. Given the burdens of treatment and poor prognosis, older adults with end-stage kidney disease would benefit from upstream interventions that both improve decision making about dialysis and promote timely receipt of palliative care in order to clarify goals, address symptoms and reduce unwanted invasive procedures. This proposal serves the long-term goal of increasing the use of palliative care for older patients with life-limiting illnesses and reducing unwanted invasive treatments at the end of life. ?Best Case/Worst Case: A Multisite Randomized Clinical Trial of Scenario Planning for Patients with End-Stage Kidney Disease? is a five-year R01 that responds specifically to PA-18-502 for development and evaluation of innovative decision aids for seriously ill older patients and/or their proxy decision makers. Our research team has developed a novel communication tool called ?Best Case/Worst Case? that employs scenario planning and a graphic aid to illustrate options, acknowledge uncertainty and describe outcomes within the context of the patient's underlying health and prognosis. We have pilot-tested this intervention for patients with kidney disease and demonstrated that nephrologists can use this tool to improve decision making about dialysis and this may increase utilization of palliative care. We are now ready to test the intervention in a large-scale efficacy study. We propose a multisite cluster randomized trial in which 320 patients making a dialysis initiation decision receive nephrologist communication using the Best Case/Worst Case tool, or communication as usual. We aim to test the effect of the Best Case/Worst Case intervention on receipt of palliative care and intensity of treatment at the end of life (Aim 1), quality of life (Aim 2), and the quality of communication (Aim 3) for older patients with end-stage kidney disease. This award will allow us to test an intervention that is easily scalable and can be disseminated rapidly for use with older patients with life-limiting kidney disease. The research is innovative because it tests scenario planning ?a decision-making strategy that has been successfully applied in business and government?but is not widely used in healthcare. The research is significant because if the intervention is effective, it has the potential to transform how specialists talk about options and dramatically improve receipt of palliative care. Our multidisciplinary team has a long history of collaboration. We are well positioned to achieve our objectives within the scope of this award given our strong pilot data and commitment from the Palliative Care Research Cooperative Group and its nephrologist-members to conduct this study.